Liquid-level indicator



Fave? H. J. G. RUDOLF LIQUID-LEVEL INDICATOR Sept. 15, 1942.

Filed May 5, v les? Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE LIQUID-LEVEL INDICATOR.

Henry J. GL. Rudolf, Galesburg, Ill.,V assignor, by

direct and mesne assignments, to .The Applied Mechanics Co.; Wellesley, Mass., a corporation of Massachusetts Application May 5, 1937, serial No. 140,872

3 Claims.

This invention relates. to indicatingmechanisms and more particularly to liquid-level indicators of the` type comprising` a casing having a depending plug; adapted to thread into an opening inthe topof a. tank. Objects of theinvention are to provide a mechanism which is simple and inexpensive in construction' and accurate and durable in use, which "can be readily assembled and disassembled-which can be fabricated' from parts which can, be readily and'. inexpensively manufactured, which has. minimum friction and therefore is responsive to slight changes in liquidlevel, which has substantially no loss-motion` and is therefore extremely accurate, which automatically prevents, overflow' through the opening in which the` device is mounted.A whiclilcan be manually actuatedexteriorly of its casingto check the operability ofl the interior mechanism, which is equally accurate during either riseor fallY of the liquid-level Within thetank and which is generally` superior to prior indicators for the same general purpose.

In one aspect the present invention involves pulleys, preferably in the form of drums, and belts, preferably in the form of tapes; adapted to wind upon the peripheryofV-the; pulleys. Two of the pulleys are arranged in alignment and` one of the belts is adaptedv to: wind upon either pulley from the other pulley.' A spring is associated with one pulley to Wind the belt onf. that pulley from `the other pulley,` and control' means `including a float are arranged to'actuate the other pulley against the action of the spring. One of the pulleys is preferably larger than. the other and' an indicatoris associated with the larger pulley. Another large: pulley islpreferably interconnected with; the smaller pulley, as for example by'fastening the twopulleys toa common axle, with a second belt having a portion wound on the-third pul-Y ley and another portion connected with the aforesaid float. By making the pulleys in the formof drums and? the belts'inthe. form of tapes, the belts wind smoothly on and or the vpulleys Without a tendency to jump off or wind irregular-l ly. The peripheries of the drums are preferably provided withvtransverse wire bails: Orptherforn of elongate anchors extending across the peripheries of the drums over which the folded ends of the tapes may readily be hooked to attachl the tapes tothe drums. The axles for the drums" are preferably mounted in the indicator casingby means of: a U-shaped bracket having inturned endsV tol receive corresponding ends: of the axles respectively. In another aspect of the invention` the float has uniform rectangular vertical crosssections from endto end so that itslwetted perimeter is the same at all oating levels, thereby improving the1accuracy of the indications; In still another aspect of the invention one of theaforesaiddrums comprises two cup-shaped sheet-metal. parts disposed bottom to bottom, thereby affording a very reliable and inexpensive Way of forming the drum. InA a further `aspect of the invention the device comprises a tube extending throughan opening in the aforesaid threaded plug; the upper endgof the tube being expanded over a part of the indicator to anchor the indicator casing to the plug, the lower end of this tube also preferably serving as a valve seat against-,which a valve on the float is adaptedA to seat to prevent overflow of liquid through the indicator casing. In still another aspect the invention comprises manually operable means exterior rof thecasing with which to actuate the indicator drum independentlyof the oa't, thereby tov check the operability of then device.

For the operation of gauges of the type herein referred tot verylittle power is available. Consequently their accuracy is seriously affectedby friction between the moving parts and particles ofdirt which nd their Way into the mechanism. By using drums and tape instead of gears the friction andy effect of dirtare minimized, therebyl greately increasing the sensitivity and accuracy of the device. 'Whereas Wire cable requires special grooves on the pulleys (and even then often jumps off or bunches on the pulleys) the tapes require only smooth-surface drums of simple con-V struction and have substantially no tendency to jump off the drums or bunch on the drums.

For the purpose of illustration atypical em bodiment of-the invention` is shown in the accompanying drawingin which, v

Fig.. l isan elevation of the device mounted in a tank; l

Fig. 2` is anV enlarged vertical cross-section;

Fig. 3 is a horizontal. sectionon line 3 3 of Fig.` `2;

Fig. 4` is anlelevationv of the indicator drum with` its associated spring, axle and belt;

Fig. 5 isa section on line 5-5 of Fig. 4 with the belt` omitted.; Y Y

Fig.` 6 isa section on line @7 5 of Fig. 2 with thebelt omitted; and

Fig. 'l is a section on line 'I-l of Fig.. 2.

The particular embodiment of the invention chosen for the purpose of illustration., comprises a` plug l adapted tothread into an opening in the top `of ra tank suchas. shown aty 2, a cup-shaped casing 3. mounted on-r the plug by means of a strap saddle 4 and bolts 5 and a tube 6 fast in an opening in the plug I and having its upper end flanged outwardly over the periphery of an opening in the strap 4, and a cover 1 telescoping over the open end of the cup-shaped casing 3, the cover 1 having a transparent window 8 which is preferably in the form of a magnifying glass to facilitate reading the indication of the indicator inside the casing.

As shown in Fig. 3 a U-shaped bracket 9 is mounted inside the casing 3 by means of screws I0, the ends of the bracket being bent inwardly at 90 to form inturned anges II and the cover 1 being secured to these flanges by means of screws I2. Pivotally mounted on the bracket v9 are two axles I3 and I4. Fast to the axle I3 is a large drum I5 and fast to the axle I4 are two drums, a large drum I6 and a small drum I1, thev latter drum being in alignment with the drum I5. The drums I5 and I1 are interconnected by a thin metallic belt I8, the opposite ends of which are secured to the two drums respectively. One end of the belt is secured to the drum I5 by foldingthe end of the belt inwardly through 180 and hooking the folded end over a bail I9 secured to the periphery of the drum by a solder or otherwise as illustrated in Fig. 5. The other end of the belt I8 is riveted, soldered or otherwise secured to the drum I1 as indicated at 20 in Fig. 3. A coil spring 2I surrounds the axle I3 with one end secured to the drum I5 as indicated at 22 and the other end 23 hooked over the bracket 9, the spring tending to rotating the drum I5 in a counterclockwise direction (Fig. 2).

A second tape 424 is wound upon the periphery of the drum I6, its upper end beingfolded under 180 and hooked over an anchor 25 which lmay be in the form of a wire soldered to the anges of the pulley of the drum as illustrated in Fig. 6. The tape 24 extendsrdownwardly through a guide slot 30 in the periphery of the casing 3 and the lower end of the tape is anchored to the float 26 which carries a valve 21V of cork or other suitable material adapted to seat against the lower end of the tube 6 when the tank is lled. The oat has the same square cross-section throughout its length, vwhereby thevwetted perimeter of the oat is always the same irrespective of the depth to which the float is submerged in the liquid. Fig. 1 shows the loatrin end elevation and Fig. 2 in side elevation. l

The tapes I8 and 24 are preferably formed of beryllium copepr which is unique in having all the desirable vcharacteristics for this purpose without `any of the disadvantages of other materials. Tapes of beryllium copper may be formed very thinly without danger of breaking or becoming permanently deformed; they are hard and springy but not brittle and they are non-corrosive.

The pulley I5 carries the Vdial indications on its front side as indicated in Figs. 1 and 2, these indications preferably being printed onthe sheet lmetal before it is shaped into the form of a by turning the handle 40 counterclockwise the float may be lifted above the liquid and then permitted to drop back. If the indicator returns to its former position the operator knows that the device is functioning properly.

When the liquid-level in the tank 2 is falling the oat 26 gradually settles downwardly, thereby unwinding the tape 24 from the drum I6, turning the drums I6 and I1 in a counter-clockwise direction (Fig. 2), winding the tape I8 from the drum I5 to the drum I'I, and turning the drum I5 in a clockwise direction (Fig. 2) against the action of the spring 2I. During the rise of liquid-level the action is reversed, the spring 2I keeping the tapes taut.

The preferred method of assembling the parts is rst to insert the drum I5, with its associated axle I3 and spring 2l, by springing the flange II of the bracket 9 outwardly far enough to permit the insertion of the ends of the axle into the openings in the bracket. With the tape I8 wound upon the drum I1 this drum, together with its associated axle I4 and drum I6, is then inserted in the bracket by springing the other fla-nge II outwardly.. The drum I5 is then turned in a clockwise direction about three turns thereby to wind thespring 2l, after which the end of the tape I8 is hooked over the bail I9 of the drum I 5. The spring 2I is then permitted to rotate drum I5 about two turns in a counterclockwise direction, thereby to wind part of the tape I8 from the drum I1 to the drum I5. This action of the spring 2I is stopped when the bail 25 on drum I6 faces the slot 30 in the casing 3, at which position the upperend of the tape 24 can be conveniently hooked over the bail 25. Of course the parts are so correlated that when the oat 26 is in the upper position shown in Fig. 2 the Full indication on the drum I5 shows through the window 8 and when the float 26 rests on the bottom of the tank the word Empty shows through the window.

The use of drums and tape instead of gears afiords a number of advantages. Not only are friction and lost-motion greatly reduced but particles of dirt are compressed between the turns of belt without offering substantial resistance to the movement of the parts and without substantially affecting the accuracy of the indication. Moreover the parts are reduced in number, particularly when one drum is utilized as a dial; and the construction is more economical, not only because of the difference in the individual parts but also because of the greater ease with which they can be aligned and kept in alignment.

By forming the slot 38 in the periphery of the casing 3 the tape is guided and prevented from twisting without the necessity of a separate plug or other guide.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim: n

1. A liquid-level indicator for attachment to an opening in the top of a tank, comprising a casing having a window in one wall, means for mounting the casing over said opening, two shafts mounted in the casing with their axes intersecting said wall, a drum on one shaft with the cuter marginal portion of one side of the drum in juxtaposed overlapping relation to said window and with calibrations on said side of the drum distributed crcumferentially around said marginal portion, small and large drums on the other shaft, the small drum being aligned with said iirst drum with a tape kinematically interconnecting the two drums, one end of the tape being anchored to the small drum and the other end of the tape being anchored to said rst drum, the large drum overlapping the side of the first drum opposite to said calibrated side, a float, a float tape Wound on said large drum, and a spring associated with said first drum for holding said first tape taut and tending to wind the float tape on said large drum.

2. A liquid-level indicator for attachment to an opening in the top of a tank, comprising a cylindrical casing having a window in one end Wall near lthe axis of the casing, means for mounting the casing over said opening, two shafts mounted in the casing with their axes intersecting said wall on opposite sides of said window, a drum on one shaft with the outer marginal portion of one side of the drum in juxtaposed overlapping relation to said window and with calibrations on said side o1 the drum distributed circumferentially around said marginal portion, small and large drums on the other shaft, the small drum being aligned with said rst drum with a tape kinematically interconnecting the two drums, one end o1 the tape being anchored to the small drum and the other end of the tape being anchored to said rst 3u drum, the large drum overlapping the side of the first drum opposite to said calibrated side, a float, a float tape Wound on said large drum, and a coil spring surrounding said second shaft for holding said first tape taut and tending to wind the float tape on said large drum.

3. A liquid-level indicator for attachment in an opening in the top of a tank, comprising a casing having a window in one side, means for mounting the casing over said opening, an axle mounted in the casing to rotate about an axis intersecting said wall adjacent said window, a drum having a disk-shaped end fast to the shaft and an integral peripheral ang'e extending at right-angles from said end, the outer marginal portion of one side of said end facing said window and having calibrations thereon, a second axle mounted in the casing parallel to the first axle, large and small drums on said second shaft, a tape having one end fast to said flange of the first drum and the other end fast to said small drum, the tape extending from one drum to the other drum across the plane dened by the axes of the two drums, a float in the tank, means kinematically interconnecting said large drum and float through said opening including a tape wound on the large drum, and a coil spring on said first axle for holding said first tape taut and tending to Wind said second tape on the large drum.

HENRY J. G. RUDOLF. 

